This study is aimed at determining the diffusion coeffcient of net-work modifiers（mainly Na, K, and Ca） in a two-phase melt-NaCl system, in which the melts are granitic andthe system is NaCl-rich in composition. The...This study is aimed at determining the diffusion coeffcient of net-work modifiers（mainly Na, K, and Ca） in a two-phase melt-NaCl system, in which the melts are granitic andthe system is NaCl-rich in composition. The diffusion coefficients of Na, K, and Ca were measured at the temperatures of 750 -1400℃, pressures of 0. 001×108 - 2×108 Pa, and initialH2O contents of O wt% - 6. 9 wt% in the granitic melts. The diffusion coefficients of Fe andMg were difficuIt to resolve. In all experiments a NaCl melt was present as well. In the absence of H2O, the diffusion of net-work modifiers folows an Arrhanious equation at 1 ×105 Pa:lgDCa= - 3. 88 - 5140/ T, lgDK = - 3. 79 - 4040/ T, and lgDNa=- 4.99 - 3350/ T,where D is in cm2/s and T is in K. The diffusion coefficients of Ca, Na, K, and Fe increasenon-linearly with increasing H2O cOntent in the melt. The presence of about 2 wt% H2O inthe melt will lead to a dramatical increase in diffusivity, but higher H2O content has only a minor effect. This change is probably the result of a change in the melt structure when H2O ispresent. The diffusion coefficients measured in this study are significantly different from thosein previous woks. This may be understood in terms of the "transient two-liquid equilibrium"theory. Element interdiffusion dapends not only on its concentration, but also on its activity coefficient gradient, which is reflected by the distribution coefficient, of the two contactingmelts.展开更多
Three-phase NaCl-H_2O fluid inclusions featuring halite dissolution temperature（Tm）higher than vapor bubble disappearance temperature（T_h） are commonly observed in porphyry copper/molybdenum deposits,skarn-type de...Three-phase NaCl-H_2O fluid inclusions featuring halite dissolution temperature（Tm）higher than vapor bubble disappearance temperature（T_h） are commonly observed in porphyry copper/molybdenum deposits,skarn-type deposits and other magmatic- hydrothermal ore deposits.Based on ｜ΔV_1｜（the absolute value of volume variation of NaCl-H_2O solution in a heating or cooling process of inclusions）= ｜ΔV_s｜（the absolute value of volume variation of the halite crystal in a heating or cooling process of inclusions） and on the principle of conservation of the mass of NaCl and H_2O,we systematically calculated the densities of NaCl-H_2O solutions in the solid-liquid two-phase field for temperatures（T_h） from 0.1℃ to 800℃ and salinities from 26.3 wt%to 99.2wt%.Consequently for the first time we obtained the upper limit of the density of NaCI-H_2O solutions in the solid-liquid twophase field for T_b〈T_m inclusions with variant salinities.The results indicate that for inclusions of the T_h〈T_m type with the same T_h,the higher the T_m or salinity is,the higher the density of the NaClsaturated solution will be.If a group of fluid inclusions were homogeneously trapped,they must have the same T_h value and the same T_m or salinity value.This may be used to distinguish homogeneous,inhomogeneous,and multiple entrapments of fluid inclusions.展开更多
Graphene-like N,S-codoped bio-carbon nanosheets(GNSCS) were prepared by a facile and environment-friendly NaCl non-aqueous ionic liquid route to house sulfur for lithium-sulfur battery. The natural nori powder was cal...Graphene-like N,S-codoped bio-carbon nanosheets(GNSCS) were prepared by a facile and environment-friendly NaCl non-aqueous ionic liquid route to house sulfur for lithium-sulfur battery. The natural nori powder was calcined at 900°C for 3 h under Ar, in which NaCl non-aqueous ionic liquid can exfoliate carbon aggregates into nanosheets. The structural characterization of GNSCS by a series of techniques demonstrates the graphene-like feature.When evaluated as the matrix for sulfur cathode, GNSCS/S exhibits more prominent cycling stability and rate capability.A discharge capacity of 548 mA h g-1 at a current density of 1.6 A g-1 after 400 cycles was delivered with a capacity fade rate of only 0.13% per cycle and an initial Coulombic efficiency(CE) as high as 99.7%. When increasing the areal sulfur loading up to 3 mg cm-2, the discharge capacity can still be retained at 647 mA h g-1 after more than 100 cycles with a low capacity degradation of only ~0.30% per cycle. The features of N/S dual-doping and the graphene-like structure are propitious to the electron transportation, lithium-ion diffusion and more active sites for chemically adsorbing polysulfides. It is anticipated that other functional biochar carbon can also be attained via the low-cost, sustainable and green method.展开更多
文摘This study is aimed at determining the diffusion coeffcient of net-work modifiers（mainly Na, K, and Ca） in a two-phase melt-NaCl system, in which the melts are granitic andthe system is NaCl-rich in composition. The diffusion coefficients of Na, K, and Ca were measured at the temperatures of 750 -1400℃, pressures of 0. 001×108 - 2×108 Pa, and initialH2O contents of O wt% - 6. 9 wt% in the granitic melts. The diffusion coefficients of Fe andMg were difficuIt to resolve. In all experiments a NaCl melt was present as well. In the absence of H2O, the diffusion of net-work modifiers folows an Arrhanious equation at 1 ×105 Pa:lgDCa= - 3. 88 - 5140/ T, lgDK = - 3. 79 - 4040/ T, and lgDNa=- 4.99 - 3350/ T,where D is in cm2/s and T is in K. The diffusion coefficients of Ca, Na, K, and Fe increasenon-linearly with increasing H2O cOntent in the melt. The presence of about 2 wt% H2O inthe melt will lead to a dramatical increase in diffusivity, but higher H2O content has only a minor effect. This change is probably the result of a change in the melt structure when H2O ispresent. The diffusion coefficients measured in this study are significantly different from thosein previous woks. This may be understood in terms of the "transient two-liquid equilibrium"theory. Element interdiffusion dapends not only on its concentration, but also on its activity coefficient gradient, which is reflected by the distribution coefficient, of the two contactingmelts.
基金supported by China National Natural Science Foundation(No.4997032)the Basic Business Fee Special Foundation for Chinese central nonprofit research institutes(K0710)
文摘Three-phase NaCl-H_2O fluid inclusions featuring halite dissolution temperature（Tm）higher than vapor bubble disappearance temperature（T_h） are commonly observed in porphyry copper/molybdenum deposits,skarn-type deposits and other magmatic- hydrothermal ore deposits.Based on ｜ΔV_1｜（the absolute value of volume variation of NaCl-H_2O solution in a heating or cooling process of inclusions）= ｜ΔV_s｜（the absolute value of volume variation of the halite crystal in a heating or cooling process of inclusions） and on the principle of conservation of the mass of NaCl and H_2O,we systematically calculated the densities of NaCl-H_2O solutions in the solid-liquid two-phase field for temperatures（T_h） from 0.1℃ to 800℃ and salinities from 26.3 wt%to 99.2wt%.Consequently for the first time we obtained the upper limit of the density of NaCI-H_2O solutions in the solid-liquid twophase field for T_b〈T_m inclusions with variant salinities.The results indicate that for inclusions of the T_h〈T_m type with the same T_h,the higher the T_m or salinity is,the higher the density of the NaClsaturated solution will be.If a group of fluid inclusions were homogeneously trapped,they must have the same T_h value and the same T_m or salinity value.This may be used to distinguish homogeneous,inhomogeneous,and multiple entrapments of fluid inclusions.
基金the financial supports provided by the National Natural Science Foundation of China (21601108 and U1764258)Young Scholars Program of Shandong University (2017WLJH15)+1 种基金the Fundamental Research Funds of Shandong University (2016JC033 and 2016GN010)the Taishan Scholar Project of Shandong Province (ts201511004)
文摘Graphene-like N,S-codoped bio-carbon nanosheets(GNSCS) were prepared by a facile and environment-friendly NaCl non-aqueous ionic liquid route to house sulfur for lithium-sulfur battery. The natural nori powder was calcined at 900°C for 3 h under Ar, in which NaCl non-aqueous ionic liquid can exfoliate carbon aggregates into nanosheets. The structural characterization of GNSCS by a series of techniques demonstrates the graphene-like feature.When evaluated as the matrix for sulfur cathode, GNSCS/S exhibits more prominent cycling stability and rate capability.A discharge capacity of 548 mA h g-1 at a current density of 1.6 A g-1 after 400 cycles was delivered with a capacity fade rate of only 0.13% per cycle and an initial Coulombic efficiency(CE) as high as 99.7%. When increasing the areal sulfur loading up to 3 mg cm-2, the discharge capacity can still be retained at 647 mA h g-1 after more than 100 cycles with a low capacity degradation of only ~0.30% per cycle. The features of N/S dual-doping and the graphene-like structure are propitious to the electron transportation, lithium-ion diffusion and more active sites for chemically adsorbing polysulfides. It is anticipated that other functional biochar carbon can also be attained via the low-cost, sustainable and green method.
